Glenn h



G. H. CURTISS.

FOLDING WING AIRPLANE.

APPLICATION FILED NDV. 8. I918.

1,316,280. PatentedSept. 16,1919.

UNITED STATES PATENT OFFICE.

GLENN H. GURTISS, OF GARDEN CITY, NEW YORK, ASSIGNOR TO CURTISSENGINEERING CORPORATION, OF GARDEN CITY, NEW YORK, A CORPORATION OF NEWYORK.

FOLDING-WING AIRPLANE.

Application filed November 8, 1918.

T 0 all whom it may concern:

Be it known that I, GLENN H. CURTISs, a citizen of the United States,residing at Garden City, in the county of Nassau and State of New York,have invented certain new and useful Improvements in Folding-WingAirplanes, of which the following is a specification.

My invention relates to airplanes and more particularly to airplanes ofthe folding wing type.

Airplanes of the folding wing type are broadly old. Patent No. 1,223,317issued to me April 7th, 1917, may be cited by way of example. Thispatent, like a number of other patents, discloses the idea of foldingwings backwardly substantially in the plane of the fuselage or body.Such an arrangement, while advantageous from one point of view, is moreor less objectionable in that interference between either the wings orthe ailerons and the enipennage of the craft is bound to exist. Thisinterference is especially objectionable where the ailerons, mounted atthe wing tips, are of the trailing edge type, i. 6., a type in which theailerons continue the wings rearwardly to an edge. For this reason morethan any other, the vast majority of airplanes now in use are providedwith fixed or non-foldable wings.

The machine of the present invention unlike existing machines, isprovided with wings which fold forwardly. Such an arrangement is ofparticular applicability to small machines wherein the stagger of thewings and the size of the tail surfaces (empennage) and their proximityto the wings is such that the wings cannot be folded back close to thebody without interference between it (the body) and either the aileronsor the wings. WVhen forwardly folded, the ailerons, carried by thewings, will extend outwardly or away from the body rather than inwardlyand toward it as heretofore. Moreover, the relative arrangement of thewing posts and the span or spread of both the tail surfaces and thesupporting sur faces as well as the distance between the supportingsurfaces and the tail surfaces are immaterial. When folded forwardly thearrangement of the wings is such that the empennage occupies a positionremote from the wings while the propeller or propellers (assuming thatthe machine is of the tractor type) occupy the space between the foldedSpecification of Letters Patent.

Patented Sept. 16, 1919.

Serial N0. 261,594.

wings. The wings, when folded, should preferably occupy positionssubstantially parallel with the fore and aft axis of the craft. Otheradvantages will be hereinafter disclosed. The invention per 86, however,is pointed out in the claims.

Of the drawings, wherein like characters of reference designate like orcorresponding parts,

Figure 1 is a side elevation of a biplane airplane, the dotted linesindicating the positions which the wings occupy when folded, and

Fig. 2 is a top plan view of the machine illustrated in Fig. 1, thedotted lines again indicating the folded position of the Wings.

A folding wing airplane is advantageous in that it may be housed in avery small space when not used, may be rendered ready for use quicklyand with little trouble, and when in use may be, upon landing, renderedalmost instantly storm proof by the substantial reduction in the liftingefliciency of its wings. If used in connection with a hydro machine, thewings may be folded and the machine operated as a Water craft orhydroplane. The big advantage, however, is the relative compactness ofthe machine when not in use.

In the selected embodiment of the invention a biplane airplane isdisclosed. The invention, however, is applicable to any and all types ofmachines, both land and water, and regardless of whether the machine isof the pusher or tractor type. In the machine disclosed, however, thefuselage or bodyis designated as 10, the supporting surfaces as 11-11,the landing gear as 12, the empennage as 13 and the power plant as 14.The supporting surfaces 1111 are preferably of the panel type andinclude outer panels 11 and engine section panels 15, only the outerpanels 1 1 being foldable as hereinafter pointed out. The empennage 13comprises the usual vertical stabilizer 16, vertical rudder 17horizontal stabilizer 18 and elevator fiaps 19. The power plant includesin addition to the motor (preferably inclosed in the body of the craft)a propeller 20 of the tractor type.

The outer panels 14: of the supporting surfaces are hingedly connectedas at 21 and 22 to the engine section panels 15, preferably in the planeof the wing beams (not shown) of the Wings. The hinges 21, i. 6.,

the rear hinges are preferably of a construction such that theconnection between the outer panels and the engine section panels may bequickly broken and the panels 14; folded forwardly about the hinges 22.The construction of the hinges 2:2 is such that the axes about which thewings fold forwardly extend substantially vertically so that the wings,when folded, will occupy positions at opposite sides of the fore and aftaxis of the machine preferably parallel therewith.

By folding the wings or panels 14: forwardly rather than backwardly asheretofore, all possibility of interference between the wings and thetail surfaces is avoided. This arrangement, while applicable to alltypes of machines, is especially applicable to scout machines whereinthe distance between the wings and the empennage is small. The wings,when folded, occupy positions at opposite sides of the propeller 20 andthe latter, to avoid interference with the wings, should occupy avertical or substantially vertical position.

As indicated hereinbefore, much trouble has been encountered indesigning folding wing airplanes to avoid interference between theailerons of the machine and the empennage when the wings are foldedback. It is either necessary to dispense with the trailing edge type ofaileron (which are decidedly the best) or so relate the wings to thebody of the machine as to enable the former to be folded backwardwithout interference. Indeed, if the wings are staggered, as they are inmany instances, a backward folding of the wings into positions in closeproximity to the sides of the fuselage is next to impossible. Thestagger or angular relation of the wings is such that one of the wingsinterferes. On the other hand, by folding the wings forwardly allpossibility of interference is avoided. Ailerons of the desired trailingedge type may be used for the ailerons herein designated as 23 willoccupy positions, when the wings are folded, remote from the empennagerather than in close proximity thereto as heretofore. The relativearrangement of the ailerons with respect to the fuselage or body, whenthe wings are folded, is brought out in Fig. 2. Furthermore, the wings,when folded forwardly, offer a protection for the propeller which, as iswell known, if exposed upon all sides, is often accidentally broken ormutilated due to extraneous cause.

Still another important advantage in folding the wings forwardly ratherthan backwardly is that no consideration need be given the span orspread of the wings or the relative arrangement of the wing posts otherthan such considerations as are given in the design of a machine havingnon-foldable wings. The empennage may be located as desired for it isnot necessary that the distance between the wings and the empennage begreater than the span of the wings. These advantages, together with theadvantages above pointed out, render the folding wing airplane in whichthe wings are forwardly folded a big improvement over existing typeswherein the wings are foldable backwardly.

lVhile I have described my invention in detail in its present prefer :dembodiment, it will be obvious to those skilled in the art afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Iaim in the append ed claims to cover all such modifications and changes.

That is claimed is:

1. In an aeroplane, the combination of a fuselage, an empennage, andforwardly foldable wings extended laterally out from the fuselage atpoints nearer its forward end than its rear end, the arrangement of thewings when folded, being such that they (the wings) extend forwardlybeyond the nose end of the fuselage to occupy positions remote from theempennage.

2. In an airplane, the combination of a fuselage, an empennage carriedby the fuselage, a propelling power plant including a tractor propeller,and forwardly foldable wings extended laterally out from the fuselage,the arrangement of the wings, when folded, being such that the empennageoccupies a position remote therefrom while the propeller occupies thespace between the folded wlngs.

3. In an airplane, the combination of a fuselage, an empennage carriedby the fuselage, forwardly foldable wings extended latorally out fromthe fuselage, trailing edge ailerons mounted at or near the wing tips,the relative arrangement of the ailerons and empennage, when the wingsare folded, being such that the empennage occupies a position remotetherefrom.

4:. In an aeroplane, the combination of a fuselage, a propelling powerplant including a tractor propeller, and forwardly foldable wings extendlaterally out from the fuselage, the arrangement of the wings, whenfolded, being such that the propeller occupies the space between thefolded wings.

In testimony whereof I hereunto affix my signature.

GLENN H. CURTISS.

copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. c."

